Apparatus for heating hydrocarbon fluids



June 15, 1937. w. w. GARY APPARATUS FOR HEATING HYDR'OCARBON FLU IDS Filed Oct. 26, 1934 2 Sheets-Sheet 1 FIGJ.

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UNITED STATES PATENT OFFICE APPARATUS FOR HEATING HYDROCARBON FLUIDS Wright W. Gary, Great Neck, N. Y., assignor to Gasoline Products (70., Inc., Newark, N. J., a corporation of Delaware Application October 26, 1934, Serial No. 750,082

13 Claims. (Cl. 196-118) This invention relates in general to the heating of hydrocarbon fluids and more especially to improvements in the heating of such fluids to accomplish the desired thermal conversion thereof for the production of motor fuel, such as gasoline.

In once-through cracking operations, it is highly desirable to accurately control the heat applied to the hydrocarbon fluid being heated as otherwise difliculties will be experienced, such as from coke deposition in the final or intermediate passages of the heating coil, which together with other disadvantages flowing from uncontrolled heating results in an operation in which the maximum efficiency will not be realized.

In accordance with my invention, the hydrocarbon fluid being treated may be rapidly heated in passing through the heating apparatus in a controlled manner to the desired temperature.

To accomplish the desired rapid heating of the hydrocarbon fluid, there is provided a large ratio of heating surface to hydrocarbon fluid volume, such as by the provision of numerous parallel paths for the hydrocarbon fluid, the hydrocarbon fluid in flowing through separate parallelv paths in various parts of the heating apparatus being subjected to substantially the same heating conditions.

One way of carrying out my invention is to provide a suitable shapedfurnace arrangement having troughs suitably spaced thereon for retaining a heat-transferring medium such as a molten material heated to the desired temperature by hot combustion gases produced in the To provide the large ratio of heating surface to hydrocarbon fluid volume, suitable pipes, preferably of small internal diameter, are arranged in parallel and immersed in the molten material in the various troughs. In accordance with one modification, the hydrocarbon fluid passing through the various parallel arranged tubes immersed in the molten material may be caused to flow separately from one end of the heating arrangement to the other end thereof in spiral-like paths to accomplish the desired heating of the hydrocarbon fluid. In accordance with another modification, the main stream of hydrocarbon fluid may be introduced into a manifold which is connected to a plurality of pipes extend- 5 ing around a suitable heating apparatus and imtherein heated to the desired temperature, are

thereafter conducted to another manifold for passage as a main stream to other equipment.

The major object of my invention is to provide an improved method and apparatus for heating hydrocarbon fluids to the desired temperature.

Another object of my invention is to provide an improved method and apparatus for transferring the desired heat to the hydrocarbon fluid through a medium, such as molten material, thus insuring uniform heating of the hydrocarbon fluid.

With these and other objects in view, which may be incident to my improvements, the invention consists in the parts and combinations to be hereinafter set forth and claimed, with the understanding that the several necessary elements comprising my invention may be varied in construction, proportions and arrangement without departing from the spirit and scope of the appended claims.

In order to make my invention more clearly understood, I have shown in the accompanying drawings apparatus for carrying out the same without limiting my improvements to the particular constructions, which, for the purpose of explanation, have been made the subject of il-. lustration.

In the drawings:

Figure 1 is an elevational View, with parts broken away, of a cone-shaped heating apparatus embodying my invention.

Figure 2 is a sectional view of a part of the heating apparatus of Figure 1, taken along line 2-2 of Figure '1, showing the arrangement of the various troughs for retaining a heat-transfer medium in which heat-absorbing tubes are submerged.

Figure 3 is a sectional elevational view of a modified form of apparatus embodying my invention.

Figure 4 is a sectional view of part of the heating apparatus of Figure 3 showing the arrangement of the troughs for retaining a heattransfer medium in which heat-absorbing tubes are submerg'ed.

Referring to the various figures of the drawings wherein like parts of the same apparatus are indicated by the same characters, and more particularly to Figure 1, there is illustrated a coneshaped heating apparatus or furnace chamber I, formed by-suitable walls 2, preferably made of heat conducting material, such as any of "the Well-known chromiumalloys, to prevent any oxidation or corrosion. It is to be understood that refractory material may be used, if desired.

The cone-shaped heating appartus I may be supported on a suitable base 3 and may be supplied with the necessary heat by suitable burners 4 positioned at the base thereof. The hot products of combustion pass upwardly through the heating apparatus I and may be conducted through a flue 5 to a suitable convection heating section, not shown.

In accordance with my invention, asuitable arrangement is provided for absorbing heat from the hot products of combustion passing upwardly through the heating apparatus I, the heat absorbed thereby being imparted to suitable parallel arranged tubes for conveying the hydrocarbon fluid being heated. As shown, the cone-shaped heating apparatus I is provided with a plurality of circular shaped members 6 of progressively decreasing diameter from the base positioned oneabove the other throughout the entire height of the cone-shaped heating apparatus to form a plurality of separate troughs. The members 6 are preferably arrange-d perpendicular to the base line of the heating apparatus to thereby form troughs 1 between the side thereof and the sloping walls 2 of the cone-shaped heating apparatus I. The thus-formed troughs are filled with molten material 8, which, in accordance with this invention, may be used as a heat-transferring medium to impart the desired heat to the hydrocarbon fluid passing through the parallel arranged tubes, to be later discussed. Each of the members 6 is welded at the bottom thereof to the wall 2, preferably around its entire circum- 'ference' as isindicated by the numeral 9, to make the troughs I fluid tight.

In carrying out my invention, a plurality of parallel arranged tubes for conducting the hydrocarbon fluid to be heated therethrough in parallelpaths are submerged in the molten'material retained in the troughs I formed by the members 5. The parallel arranged tubes substantial- 1y completely encircle each section of the heating apparatus from which they extend to the trough arrangement at the next highest level. As shown. hydrocarbon fluid to be heated to the desired temperature, is introduced through a suitable line II into a manifold I2 connected to a plurality of tubes. I3 which form parallel paths for the fluid to be thermally converted. After the section of the coil formed by the various parallel arranged tubes. 9 encircle the lower part of the heating apparatus I each'of these tubes is bent, as at I4, toextend upwardly to a point above the trough arrangement at the next highest level. From this point, each of the tubes is bent in an opposite direction, as at I5, to extend downwardly to the parallel tubes submerged in the trough arrangement at the next higher level, the tubes being again bent, as at I6, to form a coil section which encircles the heating apparatus at this height. The parallel arranged tubes extend around the heating apparatus at this height in the trough arrangement and are bent in a similar manner at each successive level in order to form a continuous coil throughout the entire height of the heating apparatus.

The hydrocarbon fluid after passing through the trough arrangements'at the various levels may be conducted to a manifold II. The manifold may be connected to a suitable line I8, controlled by a pressurereduction valve I9, from which the thus-heated oil is conducted to suitable apparatus for further treatment,'such as a soaking drum or an evaporator. Prior to the reduction of pressure on the thus-merged streams of oil passing through the manifold I1 and transfer line I8, a suitable quenching medium such as relatively cold oil, may be introduced through a line 20, to quench the thus-heated products prior to further treatment thereof.

In order to prevent heat loss from the heating apparatus I and the molten material heated thereby, there is provided, in accordance with my invention, a cone-shaped layer of insulating material 2|, preferably refractory material, surrounding the entire heating apparatus. The cone-shaped layer of insulating material may be provided with suitable openings 22 for inspecting the trough arrangements at the various levels. Each of the tubes forming the spiral coil may be suitably coupled together at convenient points for removing a particular tube section, if necessary. This tube section can then be replaced with another similar shaped tube section to continue the heating of hydrocarbon fluids in that particular coil. Obviously, the entire coil can be removed in a similar manner.

In Figure 3 there is shown a cylindrical shaped heating apparatus or furnace chamber 25 formed by suitable walls 26 of heat conducting material, such. as chromium alloys although refractory material may be used. The heating apparatus 25 may be supported on a suitable base, not shown, and the necessary hot products of combustion therefor may be supplied by burners 21 positioned at one end therefor.

The hot products of combustion from the burners 21 after passing through the heating apparatus 25 may be conducted through a flue 28 to a convection heating section, not shown. A plurality of troughs 29 are formed around the cylindrical shaped heating apparatus 25 at A body of molten material 31 is retained in 7 each of the trough arrangements. tion 38 is immersed in each body of molten material and is suitably connected to the separate pipe 35 provided therefor. As shown in Figure 4, each of the parallel streams passing through the pipes 35 may be conducted through the pipes 38,

connected in series, to cause the oil to circumscribe the heating apparatus 25 flve times in its passage from. the inlet of the tube section 3 l to the outlet thereof. Each of the parallel streams of oil after passing through its separate coil section 38 immersed in the separate molten baths in the separate trough arrange ments is conducted through a line 39 to a manifold M where they are merged. A suitable quenching medium, such as cool oil, may be introduced through a line 42 into the heated hydrocarbon fluid to quench it. It is preferable in this connection to introduce the required total quantity of quenching medium through the line 42. This resultsin an excess of quench being supplied atone point, but this excess decreases as the quenching oil contacts the stream of fluid at each successive level, thus greatly eliminating coking difficulties. Specifically, the quantity of quenching oil will depend upon the number of parallel A coil sec streams of hydrocarbon fluid, in this instance I8,

which means that a quantity I8 times the overall amount of quench medium required for any stream would be introduced at the top and the bottom line 39 would receive just the predetermined requisite quantity of quenching medium. The quenched products leaving the manifold 4| may be conducted through a line 42' controlled by a pressure reduction valve 43 to suitable equipment for after treatment.

In order to prevent radiation heat losses from the heating apparatus 2|, there is provided a cylindrical shaped layer of heat insulating material 44 surrounding the heating apparatus and the associated troughs for retaining the molten material. The layer of insulating material 44 may be provided with suitable openings 45 for permitting access to each of the parallel tube sections submerged in the molten material retained in the trough arrangements. Each parallel tube section may be made up of a plurality of tube lengths suitably coupled at convenient points to permit removal of any or all tube sections, if necessary.

It will be evident from the foregoing that there is provided in accordance with this invention a large ratio of heating surface to hydrocarbon fluid volume. Excessive quantities of the heattransferring medium, such as molten material, are not required and recirculation of this molten material for the purpose of reheating it is obviated. Thus, relatively small bodies of molten material are retained in each of the trough arrangements and the necessary heat for the hydrocarbon fluid passing through the tubes submerged therein is imparted through the molten material.

If, in operating the heating apparatus in ac cordance with either of the modifications, the coil section should become clogged due to coke deposition or the like, the thusclogged coil section can be cleaned by burning out the carbon with a stream of air or air diluted with aninert gas, such as nitrogen or steam. If desired, duplicate coil arrangements similars to those shown may be used, one of which upon becoming clogged being burned out while the other is used thus insuring continuous use of the heating apparatus for the thermal conversion of hydrocarbon fluids.

I While I have shown 18 tubes arranged in parallel relation for forming l8'parallel paths for the hydrocarbon fluid being thermally converted in each modification, it is to be clearly understood that the number of parallel paths may be varied depending on the heat to be imparted to the hydrocarbon fluid and other well understood factors. 7

In cracking a 35 A. P. I. gas oil, for example, in either of the illustrated arrangements, the gas oil which is preferably preheated to a temperature of about 800 F., for example, by passing it through suitable tubes in a convection heating section receiving gases from the heating apparatus, is forced through the parallel tube arrangement and heated during its passage therethrough to an outlet temperature of about 1100 F. while being maintained under a superatmospheric pressure of from.250 to 2500 pounds per square inch. The oil in passing once through the parallel tube arrangement is preferably cracked at a high crack per pass .such as from i0% to 55%, or higher, without detrimental coke deposition to, obtain a gasoline-of a high anti-knock value. r

It will be apparent from the foregoing de scrlption that my novel heating arrangement is readily adaptable to accomplish the desired heating of any particular oil stock. For instance, when it is desired to heat a determined quantity of a particular stock and the desired outlet temperature has been determined, it is possible to design a furnace in accordance with the arrangements herein disclosed to carry out the desired heating'of the particular stock.

While I have shown the troughs in both modi-' fications as being positioned on the outside of the furnace proper, it is to be clearly understood that they maybe positioned within the furnace proper, thus'eliminating the layer of insulating material. With such an arrangement, provision woud be made at the top and/or sides for removing tube sections.

Any suitable heat-transferring medium may be used in accordance with my invention. For instance, molten metal, such as molten lead or any suitable alloy of various metals, or fused salts or a mixture of fused salts may be employed.

The term molten materia referred to in the specification and claims is intended to cover any suitable metal, alloy of various metals, salts or mixtures of various salts.

The shapes of the illustrated furnaces may also be varied without departing from my invention and the surfaces defining the various shapes may be corrugated to increase the heat picked up thereby.

While I have shown and described the preferred embodiment of my invention, I wish it to be understood that I do not confine myself to the precise details of construction herein set forth, by way of illustration, as it is apparent that many changes and variations may be made therein, by those skilled in the art, without departing from the spirit of the invention, or exceeding the scope of the appended claims.

I claim:

1. In an apparatus for heating hydrocarbon fluids, a furnace chamber, means for producing hot products of combustion for said furnace chamber, a plurality of troughs connected to said furnace chamber and adapted to be heated by the hot productsof combustion, each of said troughs extending around said furnace chamber and positioned one. above the other, separate heat-absorbing tubes disposed in each trough, a body of molten material in each trough of such volume as to cover the heat-absorbing tubes therein and. means connected to said tubes for causing a plurality of streams of hydrocarbon fluid to simultaneously pass through said tubes.

2. In an apparatus for heating hydrocarbon fluids, a furnace chamber, means for producing hot products of combustion for said furnace chamber, a plurality of troughs connected to said furnace chamber and adapted to be heated by the hot products of combustion, each of said troughs extending around said furnace chamber and positioned one above the other, a plurality of tubes forming a plurality of continuous paths dis posed in each trough and extending from each trough to the next highest one, a body of molten material in each trough of such volumeas to and positioned one above the other, separate tubes said furnace chamber and adapted to be heated by the hot products of combustion, each of said troughs extending around said furnace chamber and positioned one above the other, separate tubes disposed in each trough, a body of molten material in each trough of such volume as to cover the heat-absorbing tubes therein and means connected toeach of said tubes for passing a separate stream of hydrocarbon fluid through each tube.

4. In an apparatus for heating hydrocarbon fluids, a furnace chamber, means for producing hot products of combustion for said furnace chamber, a plurality of troughs connected .to said furnace chamber and. adapted to be heated by the hot products of combustion, each of said troughs extending around said furnace chamber and positioned one above the other, a plurality of tubes forming a plurality of continuous paths disposed in each trough and extending from each trough to the next highest one, a body of molten material in each trough of such volume as to cover the heat-absorbing tubes therein, a manifold connected to said tubes and means for introducing a stream of hydrocarbon fluid into said manifold.

5. In an apparatus for heating hydrocarbon fluids, a cone-shaped furnace chamber, means for producing hot products of combustion for said furnace chamber, a plurality of troughs connected to said furnace chamber, each of said troughs extending around said furnace chamber and of progressively decreasing diameter to be positioned one above the other, a plurality of continuous tubes extendingfrom the lower trough to the upper one to form a plurality of parallel paths for hydrocarbon fluid, a separate body of molten material in eachtrough maintained at the desired temperature by said combustion gases, means for introducing. hydrocarbon fluid into each of said continuous tubes and means for merging all of the streams of hydrocarbon fluid after passing through the continuous tubes;

r 6. In an apparatus for heating hydrocarbon fluids, a cone-shaped, furnace. chamber, means for producing hot products of combustion for said furnace chamber, a plurality oftroughs connected to said furnace chamber onthe outside thereof, each of said troughs extending around said furnace'chamber on the outside thereof and of progressively decreasing diameter to be positioned one abovethe other, a plurality of continuous tubes extending fromthe lower trough to the upper one to form a plurality of parallel paths for hydrocarbon fluid, a separate body of molten material in each trough maintained at the desired temperature by said combustion gases, means surrounding said combustion, chamber and troughs-on the outside of said furnace chamber to preventheat loss there from and means for introducing hydrocarbon fluid into each of said continuous tubes.

7. In an apparatus for heating hydrocarbon fluids, a cylindrical-shaped furnace chamber, means, for producing hot products of combustion for said furnace chamber, aplurality of troughs connected to said furnacechamben-each of said troughs extending around said, furnace chamber disposed in each trough,..a body of molten material in each trough maintained at the desired temperature by said combustion gases, ar1d means connected to each of said tubes for passing a separate stream. of hydrocarbon fluid wthrough each tube. V a I fluids, a cylindrical-shaped furnace chamber,

means for producing hot products of combustion for said furnace chamber, a plurality of troughs connected to said furnace chamber on the outside thereof, .each of said troughs extending aroundsaid furnace chamber and positioned one above the other, separate-tubes disposed in each trough, a body of molten material in each trough maintained at the desired temperature by said combustion gases, means surrounding said furnace chamber and troughs to prevent heat loss therefrom, and means connected to each of said tubes for passing a separate stream of hydrocarbon fluid througheach tube.

9. In an apparatus for heating hydrocarbon fluids, a cylindrical-shaped furnace chamber, means for producing hot products of combustion for said furnace chamber, a plurality of troughs connected to said furnace chamber on the outside thereof, each of said troughs extending around said furnace chamber and positioned one above the other, separate tubes disposed in each trough, a body of molten material in each trough maintained at the desired temperature by said combustion gases, means surrounding saidfurnace chamber and troughs to prevent heat loss therefrom, means connected to each of said tubes for passing a separate stream of hydrocarbon fluid through each tube, and means for merging the separate streams of hydrocarbon fluid after passage through each of said tubes.

10. In apparatus for heating hydrocarbon fluids, a cone-shaped furnace chamber, means for applying hot products of combustion to the interior of said furnace chamber, means for removing furnace gases at the upper end of the chamber constituting the apex of the cone-shaped chamber, a plurality of annular troughs mounted upon the exteriorof said furnace chamber and positioned one above the other, a. body of molten materialin each trough adapted to be'maintained at the desired temperature by'said hotproducts V upon the exterior of said furnacechamber and positioned one above the other, abody of molten material in each trough adapted to be maintained at the desired temperature by said hot products of combustion, a bank, of tubes immersed inithe molten material ine ach of said troughs, means interconnecting the several banks of tubes in series, means for introducing the hydrocarbon fluid t'o the lowermost bank of tubes, and means for withdrawing the heated hydrocarbon fluid from the'uppermost bank of tubes.

12. In apparatus for heating v hydrocarbon fluids, acone-jshaped furnace chamber, means for applying hot products of' combustion to the in-v terior of said furnace chamber, a plurality of an-.

n'ulartroughs mounted upon the: exterior of said furnace chamber, a body 10f] molten material in each trough adapted to be maintained at the dey sired temperature by said hot products of combustion, a-Mbankof tubes -immersed in the molten material in each of said troughs, and means interconnecting the several banks of tubes in series.

13. In apparatus for heating hydrocarbon fluids, a vertically disposed furnace chamber, means for applying hot products of combustion to the interior of said furnace chamber, a plurality of annular troughs mounted upon the exterior of said furnace chamber, a body of molten material in each trough adapted to be maintained at the desired temperature by said hot products of combustion, 'a bank of tubes immersed in the molten material in each of said troughs, and means interconnecting the several banks of tubes in series.

WRIGHT W. GARY. 

